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Behavioural abnormalities such as impulse control disorders may develop when patients with Parkinson's disease receive dopaminergic therapy, although they can be controlled by deep brain stimulation of the subthalamic nucleus. We have recorded local field potentials in the subthalamic nucleus of 28 patients with surgically implanted subthalamic electrodes.(More)
UNLABELLED Dopaminergic depletion in the nigrostriatal system is the neurochemical hallmark of Parkinson's disease (PD). Although numerous efforts have been made to determine the evolution of dopaminergic depletion in PD, "in vivo" data concerning the stages of this process are still scarce. We evaluated 6-[18F]-fluoro-l-DOPA ((18)F-DOPA) and(More)
PURPOSE Patients with Parkinson's disease (PD) may have normal cognition, mild cognitive impairment (MCI) or dementia. We investigated differences in cerebral metabolism associated with these three cognitive states and the relationship between metabolism and cognitive dysfunction. METHODS FDG PET and a battery of neuropsychological tests were used to(More)
Normal actions and behaviors often require inhibition of unwanted and inadequate movements. Motor inhibition has been studied using the stop signal task, in which participants are instructed to respond to a go signal. Sporadically, a stop signal is also delivered after a short interval following the go signal, prompting participants to inhibit their already(More)
BACKGROUND AND PURPOSE White matter hyperintensities (WMHs) detected by magnetic resonance imaging (MRI) of the brain are associated with dementia and cognitive impairment in the general population and in Alzheimer's disease. Their effect in cognitive decline and dementia associated with Parkinson's disease (PD) is still unclear. METHODS We studied the(More)
We quantitatively evaluate the benefits of a higher field strength for functional brain MRI (fMRI) based on the blood oxygenation level-dependent contrast. The 3-T fMRI shows a higher sensitivity for the motor and somatosensory stimulation and more specific localization in the grey substance. The 3-T fMRI detects additional areas of activation with the(More)
OBJECTIVE Oscillatory activity in the beta band is increased in the subthalamic nucleus (STN) of Parkinson's disease (PD) patients. Rigidity and bradykinesia are associated with the low-beta component (13-20Hz) but the neurophysiological correlate of freezing of gait in PD has not been ascertained. METHODS We evaluated the power and coherence of the low-(More)
The pathophysiological process underlying cognitive decline in Parkinson's disease is not well understood. Cerebral atrophy and hypometabolism have been described in patients with Parkinson's disease and dementia or mild cognitive impairment with respect to control subjects. However, the exact relationships between atrophy and hypometabolism are still(More)
The role of the plasma level of homocysteine (Hcy), as a primary outcome, and the effect of silent cerebrovascular lesions and genetic variants related to Hcy metabolism, as secondary outcomes, in the cognitive decline and dementia in Parkinson's disease (PD) were studied. This case-control study focused on 89 PD patients of minimum 10 years of evolution(More)
We sought to determine whether functional connectivity streams that link sensory, attentional, and higher-order cognitive circuits are atypical in attention-deficit/hyperactivity disorder (ADHD). We applied a graph-theory method to the resting-state functional magnetic resonance imaging data of 120 children with ADHD and 120 age-matched typically developing(More)